Device for stretching and tensioning a weft yarn

ABSTRACT

An apparatus for stretching and tensioning of a weft thread including a nozzle ( 6 ) for producing an air flow directed substantially transversely to a weft direction for deflecting a weft thread with respect to the weft direction; and a reception channel ( 8 ) for reception of a deflected weft thread, which is arranged at a distance from the nozzle with the nozzle ( 6 ) having at least one nozzle hole ( 14 ) and with the nozzle ( 6 ) being adjustably arranged in the weft direction relation to the reception channel ( 8 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an apparatus for the stretching and tensioningof a weft thread for an air jet loom in accordance with the preamble ofclaim 1 and to a loom with such an apparatus.

2. Description of the Prior Art

In DE-A-32 00 637 an air jet loom is described having a weft threadmonitor and a clamping apparatus for the stretching and holding taut ofa weft thread up to beat-up. This apparatus has a body with a half openrecess the one boundary surface of which has an air entry opening andthe other boundary surface of which has an air outlet opening. The twoopenings lie opposite to one another and are connected to an air supplyline and/or to an air suction line respectively so that an air flow canbe produced in the recess transverse to the weft direction. Through thisair flow the end section of a weft thread to be inserted is engagedafter flying through the thread monitor and deflected into the airsuction line. It has proved to be a disadvantage of these devices thatonly a directed air jet is provided for the thread deflection.

The invention is based on the object of improving the stretching andtensioning of a weft thread.

SUMMARY OF THE INVENTION

This and other objects of the present inveniton, which will becomeapparent hereinafter, are achieved by providing a nozzle having at leastone nozzle hole and which is adjustably arranged in the weft directionrelative to a closed channel for reception of a deflected web thread.

The invention has the advantages that, on the one hand, the nozzleproduces two air jets which form an air curtain and that, on the otherhand, the nozzle is adjustable relative to the channel. In this way athread deflection is guaranteed independent of the type of thread andthe weft thread is held reliably taut.

In the following the invention will be explained with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

There are shown:

FIG. 1 the position of the reed during the weft insertion,

FIG. 2 a section of a portion of a weft channel at the capture side ofan air jet loom with a first embodiment of an apparatus in accordancewith the invention,

FIG. 3 the apparatus shown in FIG. 2 with the nozzle pivoted,

FIG. 4 a partly broken open view of the apparatus in the direction ofthe arrow A in FIG. 2,

FIG. 5 a section of a portion of a weft channel at the capture side ofan air jet loom with a second embodiment of an apparatus in accordancewith the invention,

FIG. 6 the apparatus shown in FIG. 5 with offset nozzle and

FIG. 7 a partly broken open view of the apparatus in the direction ofthe arrow A in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a position of reed 1 with respect to a guide device 2having a guide channel 2 a for insertion of a weft thread 9. As shown inFIGS. 2-3, at the capture side of the loom, there are arranged, in theweft direction after the reed 1 and the guide device 2, a weft threadmonitor 3 and a stretching and tensioning apparatus 4.

FIG. 4 shows the stretching and tensioning apparatus 4 according to thepresent invention. The apparatus 4 includes a nozzle holder 5 and anozzle 6 which is mounted on the nozzle holder. The nozzle holder 5 hasa through-bore 8 which forms a channel for the reception of a weftthread 9 and a projection 10 which has a slotted bore for the receptionof the nozzle 6. The nozzle 6 comprises a body 11 with a cross-sectionresembling a rectangle with parallel long sides and rounded narrow sides(FIG. 4) and a cylindrical projection 12. In the nozzle there are formeda blind bore 13 and two nozzle holes 14 which are arranged parallel toone another and open out in the rounded side. The nozzle is rotatablymounted in the holder and secured by a non-illustrated screw. In thisway a half-open recess 15 is formed which is aligned with the guidechannel 2 a. The nozzle 6 is connected to a line 16 for the supply ofair.

In FIG. 4 the nozzle 6 is shown in a position in which the nozzle holesare aligned with the channel and analogously to the prior art. As aresult of the intersecting air jets the known problems arise. If theconveying air flow for the weft thread is stronger than the air flowfrom the nozzle 6 the weft thread 9 is not correctly deflected andtensioned. If the air flow from the nozzle 6 is stronger the conveyingair flow for the weft thread, then the weft thread is already deflectedprior to reaching the apparatus. Thus the intersecting air flows must bematched to one another which is very complicated. In the firstembodiment of the apparatus this matching of the air flows isfacilitated in an advantageous manner by pivoting of the nozzle 6 andthus of the air curtain that is produced (FIG. 3).

The FIGS. 5 to 7 show a second embodiment of the apparatus. As FIG. 7shows a nozzle holder 21 is subdivided in this apparatus into a basicbody 22 with the channel 8 and a plate-like holding element 23 for thenozzle 6. The holding element 23 is provided with a slotted bore inwhich the nozzle 6 is arranged and it can be secured to the base body bymeans of the screw 26. As FIG. 7 shows the holding element 23 is soarranged that on the one end the half-open recess 15 is formed and onthe other hand the nozzle openings of the nozzle 6 are aligned with theopening of the channel 8. In the position of FIG. 5 the above explainedproblems arise which are however overcome by the pivoting of the nozzle6 in accordance with FIG. 6. In FIG. 6 the second embodiment of theapparatus is so arranged that on the one hand the half-open recess isformed and on the other hand the nozzle openings of the nozzle 6 aredisplaced opposite to the weft direction relative to the opening of thechannel 8.

As already mentioned the nozzle holes 14 are arranged parallel to oneanother. If air is supplied to the nozzle 6 then an air curtain isproduced by means of these nozzle holes 14. This air curtain extendstransverse to the air conveying flow for a weft thread. Through this aircurtain the conveying air flow for the weft thread and thus also theweft thread is urged towards the channel opening and directed into thechannel 8. In this way the weft thread is held stretched and tensionedin an advantageous manner both by the air flow from the nozzle and alsoby the conveying air flow for the weft thread. The apparatus has anozzle holder 5 with a channel 8 for the reception of a weft thread anda nozzle 6 with nozzle holes 14 for the stretching and tensioning of theweft thread. The nozzle 6 is mounted on the nozzle holder in such a waythat the nozzle is adjustable relative to the weft direction and is inparticular pivotable or displaceable. With this apparatus the idealsetting of the crossing air flows is facilitated in an advantageousmanner and a deflection of the weft thread 9 is ensured independently ofthe nature of the thread and the weft thread is held reliably taut.

What is claimed is:
 1. Apparatus for stretching and tensioning of a weftthread for an air jet loom, comprising a nozzle (6) for producing an airflow directed substantially transversely to a weft direction fordeflecting the weft thread with respect to the weft direction; and areception channel (8) for reception of a deflected weft thread, which isarranged at a distance from the nozzle, and wherein the nozzle (6) isadjustably arranged in the weft direction relative to the receptionchannel (8), and wherein the nozzle (6) is provided with two nozzleholes (14) in order to produce one of two parallel airjets and twodiverging airjets.
 2. Apparatus in accordance with claim 1, wherein thenozzle (6) is one of the displaceably arranged and pivotally arrangedwith respect to a mouth of the reception channel (8).
 3. Apparatus forstretching and tensioning of a weft thread for an air jet loom,comprising a nozzle (6) for producing an air flow directed substantiallytransversely to a weft direction for deflecting the weft thread withrespect to the weft direction; and a reception channel (8) for receptionof a deflected weft thread, which is arranged at a distance from thenozzle, wherein the nozzle (6) has at least one nozzle hole (14), andwherein the nozzle (6) is adjustably arranged in the weft directionrelative to the reception channel (8), and wherein the apparatus furthercomprises a nozzle holder (5) in which the reception channel (8) isformed and a holding section (10) for the nozzle (6), with the holdingsection having a slotted bore for receiving the nozzle (6) and means forfixing the nozzle in the bore.
 4. Apparatus in accordance with claim 3,wherein the nozzle (6) has a nozzle body (11) with a cylindricalprojection (12) rotatably mounted in the holding section (10) of thenozzle holder (5).
 5. Apparatus in accordance with claim 3, wherein thenozzle (6) has a rectangular nozzle body (11) having parallel longsides, rounded narrow sides and a cylindrical projection (12), whereinthe nozzle hole (14) opens at a narrow side, and wherein the nozzle body(11) is mounted in the holding section (10) of the nozzle holder (5) forrotation about an axis of the projection 12 so that the nozzle hole (14)is aligned with a mouth of the reception channel (8).
 6. Apparatus forstretching and tensioning of a weft thread for an air jet loom,comprising a nozzle (6) for producing an air flow directed substantiallytransversely to a weft direction for deflecting the weft thread withrespect to the weft direction; and a reception channel (8) for receptionof a deflected weft thread, which is arranged at a distance from thenozzle, wherein the nozzle (6) has at least one nozzle hole (14), andwherein the nozzle (6) is adjustably arranged in the weft directionrelative to the reception channel (8), and wherein the apparatus furthercomprises a nozzle holder (21) which has a basic body (22), with thereception channel (8) being formed in the basic body, and a holdingelement (23).
 7. Apparatus in accordance with claim 6, wherein thenozzle (6) has a nozzle body (11) with a cylindrical projection (12)rotatably mounted in the holding element (23).
 8. Air jet loom,comprising a reed (1) with a guide element (2) having a guide channel (2a); a weft thread monitor (3) arranged downstream of the reed (1) in theweft direction; and an apparatus for stretching and tensioning of a weftthread, the apparatus comprising a nozzle (6) for producing an air flowdirected substantially transversely to a weft direction for deflecting aweft thread with respect to the weft direction; and a reception channel(8) for reception of a deflected weft thread, which is arranged at adistance from the nozzle, wherein the nozzle (6) has at least one nozzlehole (14), wherein the nozzle (6) is adjustably arranged in the weftdirection relative to the reception channel (8), and wherein the atleast one nozzle hole (14) is aligned with the reception channel (8).